Explanations for the Cambrian Explosion

Doubting Too,And why is skeletonised invertebrates (note non-skeletonised ones were excluded) & not modern animal appearing in the Cambrian over the period of "about 10 million years" indicative of an intelligent designer?Mark

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There are 10 kinds of people in this world; those that understand binary, & those that don't

Hi, Doubting Too.Thanks for you comments.I think everyone else has done a good job explaining the common ancestor bit, so I'll refrain from adding my input. But, I'd like to address one thing you said: The main drawback isn't the identity of the Designer. The main drawback is that the natural world simply doesn't look like a bunch of models built from the same pool of parts, as your Honda cars do.See, Honda has a certain suite of parts that it has available to it, either by its own manufacture or by contract with other companies, and their engineers can pretty much mix-and-match and redesign any of the various parts to make a car.In nature, we don't see that. Typically, what we see is that the parts are not randomly distibuted, but dispensed in regular blocks that form a nested, hierarchical pattern. For instance, there is a group of organisms that contains a set of parts: a protein exoskeleton, jointed legs and a segmented body (we call them the arthropods). A subset of that group has the first three pairs of legs modified into mouthparts, three pairs of legs modified for walking, and a special organ in the antennae (we call them the insects). A subset of that group has two pairs of wings and a specific hingeing of the mouthparts (we call them the Pterygota).The point is that all organisms can be united in a nested sequence like this. The parts are distributed within well-defined groups of organisms. Those groups can be combined with other well-defined groups into a larger, well-defined groups that are united by parts and features common to them all. And, so on, until you can include all organisms within a single group based on shared characteristics.Try this website (the Tree of Life Web Project): they have the phylogenetic tree laid out rather well. You can see how the parts aren't randomly scattered across organisms, as the parts of cars are, but are contained within well-defined, nested groups.-----How does this relate to the Cambrian Explosion? Well, lots of paleontologists have reconstructed lots of organisms from fossils found in, before and after the Cambrian. The basic features that define most of our modern groups of animals today are found in primitive form, in some of those organisms from the Cambrian Era.Take Pikaia, for instance. It is an animal that resembles simple vertebrates (lancelets). It has a notocord (spinal cord), and muscle blocks very similar to the muscle blocks in lancelets and fish. It doesn't have a skeleton yet, but animals with skeletons are found later.

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-BluejayDarwin loves you.

Because that assumes a completely unneeded other explaination. It's like saying well, I'm sure the car drove from Leeds to here, but I think it flew from Glasgow to Leeds. Because that describes nothing like what we observe. The designed objects we can observe do not look like the natural organisms we observe, and they certainly don't form heirachies in the same way. In particular, a designed object will tend not to use multiple different solutions to a problem (unless it has multiple designers), yet every cell in your body uses two different forms of DNA encoding. Because it's not true; there are enough similarities between all forms of life to conclude that they all share a common ancestor.And because it's a deeply unsatisfying conclusion. Especially when the extrapolation is so obvious.

Hey Doubting Too,Let's see if I can add to the confusion: Technically singular is incorrect. What is correct is a common ancestral population, where the population, generation by generation, evolves. Isolated sub-populations can evolve in different ways and over time become reproductively incompatible: speciation. Here we now have two "daughter" populations that are related to a common ancestor population, with many of the hereditary traits of the common ancestor population ... but not all the hereditary traits from the common ancestor population are necessarily (or even likely) shared by either daughter population, and they each have different new hereditary traits.It is just convenient to talk about a common point of ancestry as a "common ancestor" rather than necessarily a factual single individual.You can have a population of organisms in an ecosystem that supports 100 individuals, and each generation those individuals mate, reproduce and die in various quantities such that there are still 100 individuals per generation. After several generations the hereditary traits will all be mixed together without necessarily coming directly from any single individual. They come from the pool of hereditary traits in the population as a whole (which of course is where selection comes in).One should never think of branches as being individuals, but populations, and each branch is in constant flux along it's length with new members added (reproduction) and old members dying (no longer contributing actively to the gene pool).Thus each branching point has a common pool of hereditary traits, where some contribute to one branch and some contribute to the other.COnfUsEd yet?Now back to the Cambrian "million-year-explosion" with a number of already diverse common ancestor populations and the new ability to grow calcium parts from sea-water ...Enjoy.Edited by RAZD, : topic

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In fact, Darwin, in the "Origin of Species" suggested one or several forms as a starting point. He had no reason to know if we are descended from one or from more than one population (thanks to RAZD's note).Since then we have learned a lot (a astronomical understatement) about living forms on Earth. So far all that information says that they are all tied together in a way which suggests that, however many got started, only one lineage has survived through to today.There is a possibility that we are overlooking something somewhere that is a descendant of another lineage but we have no evidence for that.

Hi Blue, Thanks, for the link. But, I observed that this "tree" is just an interpretation--an illustration (?).I dug further into the link. Tree of Life Turns Out to Have Complex Roots.That portion of article says, Another says... To my untrained mind, these scientists are in effect saying they are as confused as before. (I find comfort in the fact that I am not the only one confused. ) But, they won't stop speculating until.... WHEN? WHEN is the big question? Am I right?

The confusion continues... Now, you guys really got me confused!! My latest message also confirms that its not only me who is confused--even scientists. Refer to Message 21 the link provided by BlueJay...when explored further.If the Cambrian period indicates appearance of complex things --as if by explosion--then that doesn't prove "common ancestry". It is proof to the contrary--that life "exploded" and that supports.... what ?Edited by Doubting Too, : No reason given.

Hi, Doubting Too. No, you're still wrong.One thing you need to do is to stop using political debate tactics. Words like "speculate" are only used to slander your opponent's position.You did not notice what all that "speculating" those scientists are doing is based on, but only took hold of the part where it said, "we're not 100% positive that we're correct."I'm not even going to try to explain to you the science of phylogenetics, because it would take entirely too long, and this whole "Tree of Life" discussion is not the point of this thread, anyway. Seriously, though, if you want to debate on this issue, make sure you read a good deal of stuff, and take a class or something, before you come out with a strong position and insist that all scientists are blundering idiots. This is a newspaper article. People who write newspaper articles are trained in the arts of "spicing things up" to make them interesting. You really shouldn't read much into this.The Tree of Life is a fascinating topic, one that perhaps deserves a number of threads of its own to discuss. I provided you the link so you could understand what the tree of life implies: I never intended it to be a continuation of this discussion. If you want to start a thread about the base of the tree of life, go for it.----- Two points to be made:

1. Actually, your message only confirms that some people think scientists are confused.
2. I assure you that the people working on the Tree of Life are not nearly as confused as you are about this.

-----Now, back to the Cambrian Explosion: The "Cambrian Explosion" is an unfortunate name from the phenomenon. Just like the "Big Bang" isn't a theory about the universe "exploding" into existence from nothing, the "Cambrian Explosion" is not an example of biodiversity "exploding" out of nothing.The problem is that the evidence we have is sketchy: only a few locations on earth are known to have accessible Cambrian rocks that have fossils in them. Since each of these locations necessarily has a short date range, it looks like life suddenly appeared, because no life was found in rocks slightly older. This is what I called the "Snapshot Effect" in the Opening Post.More fossil locations and fossil analyses have become available recently, and there is no longer any reason to think that all these animals suddenly "popped" out of nowhere. For that reason, the "Cambrian Explosion" does not appear to be anything particularly unusual that needs special attention from the Theory of Evolution.

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-BluejayDarwin loves you.

Carl Woese's arguments have nothing to do with the Cambrian 'explosion'. The origin of the Eukaryotes and other kingdoms is well before the origin of the metazoa. There was a previous thread on Woese's hypothesis at Woese's progenote hypothesis.TTFN,WKEdited by Wounded King, : No reason given.

I think this link could be helpful.Cambrian FossilsFirst, of all I respectfully invite IDs / Creationists/ etc to take a look at these pictures. They say a thousand words. Forget the "conjectures", "estimates"--made by scientists in this site which obviously espouses evolution.Guys, specially creationists who are more knowlegeable than me, please help. (I thought I was among friends here. It's turning out I'll be skewered dead ! I have questions in my mind--before I'm impaled to death-- when I see these pictures:1. Blue J accused me. First, I don't see any opponents. I only see friends trying to discuss. But, be that as it may, am I not allowed to use the word "speculate" while scientists may make "conjectures" and "estimates"--words found in this site if you drill down further?2. Will not anybody have the right to interpret these data opposite what these men of science do? For example, a creationist may say: 'hey these pictures prove that account in Genesis--"let blah...blah bring forth creeping souls/ creatures"? Are these not also fair interpretation of these data?3. Looking at these 16+ picture, and relating it to the so called "tree of life" which of these do you think is Blue Jay's "ancestor"--if it could be traced ( just an example, Blue )? Could it really be traced beyond reasonable doubt? What convincing evidence will an evolutionist-scientist give me ( I understand there are also creationist-scientists)? Whom should I believe?Note: For those who will answer # 3, please consider the explanations of parasominium about "ancestor" Yeah, if I understood it correctly, my third cousins and I may have 1 common ancestor. If we extend that to the case of BlueJ and Me--which common "grand pa" would we have among the 16+ life-forms shown in the above link?4.What if some of those fosills are found still alive today? Will supporters of evolution abandon their theory?Blue J, could you please answer my question #1, please?Edited by Doubting Too, : No reason given.Edited by Doubting Too, : No reason given.Edited by Doubting Too, : No reason given.Edited by Doubting Too, : Clarity about "ancestor"Edited by Doubting Too, : No reason given.

You are confusing yourself by the use of terminology. This is in reference to the fact that it is not just one particular animal of a particular species evolves but that a population of this species undergoes evolutionary changes do to any number of effects of the environment, speciation, separation of the members of the same species etc. The point I made as to why it is a sigle common ancestor is in regards to the evolved species and not a single individual.The other problem is the use of the term "explosion." It was simply used to indicate a large number of new species that evolved during the period, particularly before much the current data was found after the term was coined.Edited by bluescat48, : spelling

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There is no better love between 2 people than mutual respect for each other WT Young, 2002Who gave anyone the authority to call me an authority on anything. WT Young, 1969

Could we use more neutral words like "came to being" instead of "evolve" and "created"? Just a suggestion, though?

As I dig deeper into this site--one espousing evolution--my confusion appears to have no end--and may be most scientists.Trilobita Trilobites So, Darwin is making speculation. Scientists aren't sure of the "cousins"...Tribulite lineage persisted some 300 million years..Question:
1. If Darwin can conjecture that the tribolite descended from one-precambrian ancestor, and if there is found today a living tribolite almost exactly the same as in the fossil--can I speculate that Darwin took us for a ride?

Can you explain to me why you think that finding a, once thought of extinct, species alive today would mean anything over all to the TOE?If you found out today that one of your great-great-great grandmothers was still alive would that mean that you weren't descended from her?

Doubting Too, Message 16 please.Mark

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There are 10 kinds of people in this world; those that understand binary, & those that don't